Papers by Keyword: Copper

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Authors: Xue Dan Chen, Min Gong, Qing Shan Fu, Xing Wen Zheng, Xue Song Feng
Abstract: The corrosion inhibition effect of the 1-alkyl-3-methylimidazolium proline ([Omi [Pro]) for copper in 3.5% NaCl solution was investigated by using electrochemical methods. The results indicated that: the inhibition efficiency of [Omi [Pro] was more than 90%, which showed the excellent corrosion inhibition performance. The inhibition efficiency increased with increasing concentration of [Omi [Pro], and decreased with increasing temperature, but it changed very little when the concentration arrived at 0.001 mol/L. [Omi [Pro] was a good mixed-type inhibitor which mainly inhibited anodic processes.
Authors: Pradel Paulina, Gino Corsini, Tello Mario, Alex González
Abstract: The adhesion of microorganisms to the floating cages in the aquaculture industry is currently controlled with copper as a biocide paints problem. The development of these activities has resulted in marine and freshwater sediments next to the culture centers high levels of copper. Due to these problems of environmental pollution, at present have been implemented new technologies of biological origin for the detoxification of ecosystems through the use of microorganisms (fungi, yeasts and bacteria). Therefore the main objective of this work is the search for marine microorganisms for the removal of copper. For this, samples were collected from marine sediment contaminated with copper Tenglo Channel (41 ° 29'23 .59 " S, 72 ° 58'06 .70" W). Gram negative bacterium of marine sediment was isolated in TSA medium supplemented with 7 mM Cu (II), this strain was designated as LMAE-2. The phylogenetic analysis has a 97 % similarity with Pantoea agglomerans. The high resistance for copper was determined at 9 mM. Finally, the metal removal capacity of this bacterium was determinate in 11.6% by Atomic Absorption Spectrometry. These results suggest that marine bacteria could be a biologic model system for use in processes for removal this toxic metal.
Authors: Qing Wei Jiang, Lin Xiao, Xiao Wu Li
Abstract: The temperature-dependent deformation and damage behaviors of ultrafine-grained (UFG) Cu and Ti produced by equal channel angular pressing (ECAP) were investigated and compared. It was found that ECAPed materials with different crystalline structures, e.g. the present fcc Cu and hcp Ti, exhibited significantly distinctive high-temperature deformation and damage characteristics. As the testing temperature is below recrystallization, small- and large-scale cracks or voids formed along the shear bands (SBs) on the surface of UFG Cu, whereas only a few fine shear lines and some non-propagation voids appeared on the surface of UFG Ti. As the temperature is above recrystallization, some small cracks (or voids) formed along grain boundaries and slip deformation took place in many coarsened grains, while only extrusions and intrusions instead of obvious cracks or voids are observable for UFG Ti. The corresponding microstructual changes after compressive deformation, e.g. grain coarsening, were also examined and confirmed by TEM observations.
Authors: Xing Ke Shang, Zhuo Yue Lan, Qi Fu Zhang, Ting Ting Li
Abstract: With the depletion of mineral resources, more attention is paid on the secondary resources to recover valuable metals. In this paper, a research is carried out to recover copper and iron from copper smelting slag by flotation and magnetic separation. The influence of grinding fineness and collectors on flotation of copper are investigated. A copper concentrate is obtained by flotation and an iron concentrate is obtained by magnetic separation in the closed circuit flowsheet. The copper concentrate contains 18.86% Cu with a recovery of 72.36%, and the iron concentrate contains 52.24% Fe with a recovery of 70.87%.
Authors: Chong Yang Gao, W.R. Lu
Abstract: In this paper, a constitutive description of the true stress-strain behaviors of nano-twinned metals has been proposed. The size effects of nano-scale twin boundaries (TBs) and ultra-fine grain boundaries (GBs) are considered in the athermal stress. The evolution of the dislocation density with strain under the influence of strain rate and temperature is introduced in the thermal stress based on our previous meso-scale constitutive model. The new model can effectively describe the strength transition regime in nano-twinned metals. The proposed model’s predictions of true stress-strain relation curves for nano-twinned copper are compared with the experimental results of uniaxial tension tests for validation. The comparisons show that the previous models in literature for the dependence of initial yield strength on twin spacing cannot describe the experimental data correctly when the twin spacing tends to zero; however, the phenomenological model proposed in this paper for the twin spacing depending relation is theoretically rational and can well describe the experimental data in the whole range of twin spacing.
Authors: Ke Tong, Fei Ye, Ya Kun Wang, Feng Zhou
Abstract: The preferential sites for vacancies on a series of symmetric tilt grain boundaries in copper have been investigated by molecular dynamics simulation. The regularity of preferential sites for vacancies on these boundaries can be described by the structural unit model. This is essential because of the correspondence between the geometries of the structural units and the local stress field. The vacancies are energetically preferred at the sites with relatively large tensile stress, and these sites are the corner sites of the structural units. Moreover, these preferential sites are mainly related to the structural unit types irrespective of which grain boundary that the structure units locate in. Therefore, the preferential sites for vacancies on various grain boundaries formed by combinations of certain structural units can be readily described and predicted by the structural unit model.
Authors: Jia Rui Jin, Yuan Zhi Chen, Hui Zhang Guo, Zhen Wei Wang, Dong Liang Peng
Abstract: A non-aqueous synthetic route has been developed for the preparation of uniform Cu nanowires with length up to tens of micrometers. Unlike commonly used one-pot synthesis approach that usually involve a fast reduction of metal precursors in the presence of reducing agents, a continuous-injection approach has been to utilized to control the speed of reaction and the concentration of Cu nuclei. In this approach, copper (II) chloride dihydrate and nickel (II) acetylacetone which are dissolved in oleylamine solutions have been injected into octadecene by a syringe-pump. The as-prepared samples have been characterized by transmission electron microscopy, scanning electron microscopy and energy-dispersive X-ray spectroscopy. The results show that the products are pure Cu nanowires which have preferred <110> growth directions. The formation mechanism and major influencing factors on the synthesis of Cu nanowires have been discussed.
Authors: Dan Li
Abstract: Well-dispersed and hydrophilic copper nanoparticles have been synthesized from an organometallic precursor in an organic (or oil) phase. There are two layers coated on the surface of the copper nanoparticles. The coating layer can not be dissolved or rinsed off by organic media. The changing of viscosity and enhancement of the thermal conductivity of copper nanofluids is also presented.
Authors: Hui Zhang, Zi Feng Ni, Qing Zhong Li
Abstract: In this paper, a kind of alkaline slurry was introduced, in which silica was used as the abrasive, H2O2 was used as the oxidize, glycine was used as the complexing agent, azimidobenzene was used as the surfactant, and borax was used as the pH regulator. The atomization polishing method was used, and the effects of the traditional polishing and atomization polishing were compared. After the atomization polishing, the surface roughness of copper was 7.61 nm and the material removal rate was 188 nm/min; After the traditional polishing, the surface roughness was 15.22 nm and the material removal rate was 236 nm/min. The dosage of polishing slurry used in the atomization polishing is dozens of times less than that in the traditional polishing.
Authors: Jia Hai Ye, Ling Jun Duan, Lian Lian Jin
Abstract: Abstract. The novel tetraphenylethylene (TPE) based sensor 1 bearing bis(2-pyridin-2-ylmethyl) amine (BPA) unit and BODIPY unit linked with triazole moieties could be obtained by click reaction efficiently. It was employed as a fluorescence probe for the selective recognition of Cu2+ and Co2+. They form stable 1:1 stoichiometric complexes and the lowest limit of detection was 1×10-7 M.
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